A rail train is constituted by coupling a plurality of railcars one another, and each of the railcars is constituted by mounting a carbody on a bogie. For example, as shown in FIGS. 15 and 16, couplers 3A and 3B for the coupling with the other car are provided on an underframe 2 positioned at a bottom portion of the carbody. As in PTLs 1 and 2 for example, each of the couplers 3A and 3B includes a structure for absorbing a collision load (impact energy) at the time of collision.
The coupler 3A shown in FIG. 15 is provided at a head portion of a first car and is configured to couple the first cars each other. The coupler 3A is an automatic tight lock coupler (for example, Scharfenberg coupler of Germany) including a cylinder mechanism 4A and an impact absorbing pipe 5A. A coupling mechanism 6A for the coupling with the other car is attached to a tip end portion of the cylinder mechanism 4A, and the impact absorbing pipe 5A is attached to a base end portion of the cylinder mechanism 4A. The cylinder mechanism 4A and the impact absorbing pipe 5A absorb an impact load by two-step contraction (or deformation).
The coupler 3A configured as above includes an attachment flange 7A between the cylinder mechanism 4A and the impact absorbing pipe 5A. The attachment flange 7A is fastened and attached to an attached flange portion 8A of the underframe 2 by coupler attachment bolts 9A. An underfloor device 10A is provided behind the coupler 3A. Examples of the underfloor device 10A are a junction box, a bogie, and the like. The junction box is a protection box for electrical devices, air pipes, and contacts and terminals used to couple, branch, or relay electric wires.
The coupler 3B shown in FIG. 16 is provided at a tail portion of the first car and is configured to couple the first car and a middle car. The coupler 3B includes the same components as the coupler 3A (for example, a cylinder mechanism 4B and a coupling mechanism 6B) but is different from the coupler 3A in that an impact absorbing cushion member 5B is included. The impact absorbing cushion member 5B includes an elastic member, such as rubber. At the time of collision, the impact absorbing cushion member 5B fulfills the same function as the impact absorbing pipe 5A used in the first car. As with the coupler 3A, the coupler 3B configured as above includes an attachment flange 7B. The coupler 3B is attached to the underframe 2 such that the attachment flange 7B is fastened to an attached flange portion 8B of the underframe 2 by coupler attachment bolts 9B. An underfloor device 10B is provided in front of the coupler 3B.
The railcar absorbs the impact of the collision by the couplers 3A and 3B. However, the amount of energy the cylinder mechanisms 4A and 4B, the impact absorbing pipe 5A, and the impact absorbing cushion member SB can absorb has an acceptable limit. If the load applied to the couplers 3A and 38 exceeds the acceptable limit, the coupler attachment bolts 9A and 9B break, and the couplers 3A and 3B are separated from the attached flange portions 8. By this separation, excessive reaction force is prevented from being applied to the carbody.